THREE ROLLING-CUTTER DRILLING BIT Russian patent published in 2003 - IPC

FIELD: three rolling-cutter drilling bits for well drilling. SUBSTANCE: drilling bit has rolling cutters and hard-alloy teeth installed on peripheral and nose teeth rows of rolling cutters. The first rolling cutter is provided with single-line peripheral teeth row, and the second and third rolling cutters, with two-line peripheral teeth row. Peripheral teeth row of the second rolling cutter has larger number of teeth in internal line than in external one. The second and third rolling cutters are provided with gage teeth row, and peripheral teeth row of the third rolling cutter has less number of hard-alloy teeth in internal line than in external one. Installed on the second rolling cutter in clearance of conventially the first and second hard-alloy teeth of internal line of peripheral teeth row is one hard-alloy tooth of external line of peripheral teeth row; installed in clearance of the second and third hard-alloy teeth is one tooth of gage teeth row; installed in clearance of the third and fourth teeth, first, is hard-alloy tooth of external line of peripheral teeth row, and then, one tooth of gage teeth row; installed in clearance of the fourth and fifth hard-alloy teeth is one hard-alloy tooth of external line of peripheral teeth row; installed in clearance of the fifth and sixth hard-alloy teeth is one tooth of gage teeth row; installed in clearance of the sixth and seventh hard-alloy teeth is one hard-alloy tooth of external line of peripheral teeth row; installed in clearance of the seventh and eighth hard- alloy teeth, first, is one tooth of gage teeth row, and then, hard-alloy tooth of external line of peripheral teeth row, and further on, sequence of teeth installation is separated. Installed on the third rolling cutter, in clearance of conventionally the first and second hard-alloy teeth of internal line of peripheral teeth row are two hard-alloy teeth of external line of peripheral teeth row; installed in clearance of the second and third hard-alloy teeth, first, is one tooth of gage teeth row, and then, one hard-alloy tooth of external line of peripheral teeth row; installed in clearance of the third and fourth hard-alloy teeth, first, is one hard-alloy tooth of external line of peripheral teeth row, and then, one tooth of gage teeth row; installed in clearance of the fourth and fifth hard-alloy teeth are two hard-alloy teeth of external line of peripheral teeth row, and further on, sequence of teeth installation is repeated. EFFECT: prolonged service life of drilling bit and increased penetration rate due to more effective breakage of formed edging on bottomhole periphery and spiral ridges on well walls. 2 cl, 8 dwg